Alter Workflow::Instance and Cron to return empty hashrefs instead

of undef.
Fix JSON handling in Commerce::Transaction->shippingOptions.  This probably isn't a problem
now since it is never called as an accessor.

lib/WebGUI/Commerce/Transaction.pm

@@ -619,6 +619,7 @@ sub shippingOptions {
 		$self->session->db->write("update transaction set shippingOptions=? where transactionId=?",[$self->{_properties}{shippingOptions},$self->{_transactionId}]);
 	}
 
+    return {} unless defined $self->{_properties}{shippingOptions};
 	return from_json($self->{_properties}{shippingOptions});
 }
 

lib/WebGUI/Workflow/Cron.pm

@@ -121,7 +121,7 @@ sub get {
             return $parameters->{parameters};
         }
         else {
-            return undef;
+            return {};
         }
     }
     return $self->{_data}{$name};

lib/WebGUI/Workflow/Instance.pm

@@ -152,7 +152,7 @@ sub get {
             return $parameters->{parameters};
         }
         else {
-            return undef;
+            return {};
         }
     }
     return $self->{_data}{$name};